Needle selection synchronizing apparatus for a circular knitting machine

ABSTRACT

TIMING IMPULSES PRODUCED BY THE ROTATING NEEDLE CYLINDER OF A CIRCULAR KNITTING MACHINE AND PROGRAM REPRESENTING SELECTING IMPULSES ARE SUPERIMPOSED AND FORM DURING COINCIDENCE TIMED NEEDLE SELECTING IMPULSES CONTROLLING ELECTROMAGNETIC ACTUATING MEANS OF THE CYLINDER NEEDLES SO THAT SELECTED NEEDLES ARE OPERATED IN ACCORDANCE WITH THE PROGRAM IN EXACT SYNCHRONIXM WITH THE ANGULAR DISPLACEMENT OF THE ROTATING NEEDLE CYLINDER.

NEEDLE SELECTION SYNCHRONIZING APPARATUS FOR A CIRCULAR KNITTING MACHINE Fi led March 17, 1967 H. J. STOCK ET AL 3,561,232

INVENTORS HANS JOACHIM STOCK RICHARD SCHMIDT BY h (4J4 ul \/1 /u,

ATTQRNEY United States Patent O 3,561,232 NEEDLE SELECTION SYNCHRONIZING AP- PARATUS FOR A CIRCULAR KNITTING MACHINE Hans Joachim Stock, Freiburg im Breisgau, and Richard Schmidt, Stuttgart-Vaihingen, Germany, assignors to Franz Morat GmbH, Stuttgart-Vaihingen, Germany Division of application Ser. No. 520,938, Jan. 17, 1966. Continuation-impart of applications Ser. No. 543,455, Mar. 22, 1966, now Patent No. 3,327,499; Ser. No. 543,457, Mar. 22, 1966, now Patent No. 3,324,685; and Ser. No. 562,938, June 29, 1966, now Patent No. 3,313,128, which is a continuation-in-part of application Ser. No. 404,118, Oct. 15, 1964. This application Mar. 17, 1967, Ser. No. 624,681 Claims priority, application Germany, Mar. 6, 1965, M 64,421 The portion of the term of the patent subsequent to Apr. 11, 1984, has been disclaimed Int. Cl. D04b 15/78 US. Cl. 66-50 9 Claims ABSTRACT OF THE DISCLOSURE Timing impulses produced by the rotating needle cylinder of a circular knitting machine and program representing selecting impulses are superimposed and form during coincidence timed needle selecting impulses controlling electromagnetic actuating means of the cylinder needles so that selected needles are operated in accordance with the program in exact synchronism with the angular displacement of the rotating needle cylinder.

CROSS-REFERENCES TO RELATED APPLICATIONS The present application is a divisional application of my copending application Ser. No. 520,938, issued as US. Pat. No. 3,313,129, filed Jan. 17, 1966 and entitled Arrangement for Synchronizing Program Controlled Machine Operations With Machine Movements. The present application is also a continuation-in-part of the US. patent application Ser. No. 562,938, filed on June 29, 1966, now US. Pat. No. 3,313,128, which in turn is a continuation of the US. patent application Ser. No. 404,118, filed on Oct. 15, 1964 and now abandoned; a continuation-in-part of US. patent application Ser. No. 543,457, filed Mar. 22, 1966, now US. Pat. No. 3,324,685; and a continuation in-part of US. patent application Ser. No. 543,455, filed Mar. 22, 1966, now US. Pat. No. 3,327,499.

BACKGROUND OF THE INVENTION In order to produce a desired knitting pattern, the needles of a circular knitting machine, and particularly the cylinder needles, have to be actuated in accordance with a program, which may be represented by perforations or light permeable spots on a program tape. Since an absolutely correct synchronism between the program tape, or other program control means, with the angular displacement of the rotating needle cylinder cannot be obtained, selecting impulses may be applied to a wrong needle, causing a faulty knitting pattern.

SUMMARY OF THE INVENTION It is one object of the invention to provide means for selecting needles in exact synchronism with the angular position of the needle cylinder of a circular knitting machine.

Another object of the invention is to superimpose timing impulses which are in exact synchronism with the rotation of the needle cylinder, on selecting impulses s 3,561,232 Patented Feb. 9, 1971 that the impulses are elfective only upon coincidence, and the needle selecting operations are carried out in exact synchronism with the angular position of the needle cylinder.

One embodiment of the invention comprises a needle cylinder or dial which actuates first switching means in the form of an impulse generator to produce timing impulses of exactly the same length at exactly spaced time intervals. Program control means driven from the needle cylinder in such a manner that exact synchronism of the program control means and the needle cylinder cannot be maintained; second switching means controlled by the program control means to produce needle selecting impulses having a longer duration than the timing impulses and being timed so that during relative movement between the needle cylinder and the program control means, the timing impulses coincide with the selecting impulses; and electric actuating means connected with the first and second switching means and being energized to operate the cylinder needles only during coincidence of a timing impulses with a selecting impulse.

Consequently, the needle selecting operations are controlled in accordance with a program determined by the program control means, but in exact synchronism with the rotation of the needle cylinder and dial.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is partially a schematic plan view, and partially a circuit diagram, and illustrates one embodiment of the invention;

FIG. 2 is a fragmentary view illustrating a portion of a program tape used in the arrangement of FIG. 1; and

FIG. 3 is a diagram illustrating selecting impulses and timing impulses occurring during operation of the embodiment of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to FIG. 1, a needle cylinder 56 of a circular knitting machine has axially extending grooves separated by axially extending projections 55 and guiding cylinder needles for axial movement. At each knitting station, of which only some are illustrated in FIG. 1, an electromagnetic actuating means 54 is provided which, when energized, causes movement of a directly opposite cylinder needle in axial direction to an operative knitting position. The arrangement may correspond to the construction disclosed in the US. patent to Schmidt et al., 3,365,917.

A transmission schematically indicated at 113 connects the needle cylinder 56 with program control means including a transparent cylindrical roller 101 transporting a program tape 51 which has elongated perforations or light permeable program representing portions designated a in FIG. 2. Transporting roller 101 is driven from cylinder 56 by transmission means 113. The program tape 51 is wound in endless loops over reels 1a and 1b. A source of light 109 produces a bundle of rays passing through a condenser lens 108 and through the transparent transporting roller 101 which constitutes a cylindrical lens irrespective of its angular position. Light guiding rod means 52 receive rays passing through light permeable portions a of program tape 51, and guide the rays to photocells 103 which produce impulses supplied to a gate 44 which responds to two simultaneous impulses to assume a circuit closing position, and is of the type frequently referred to as an AND-gate. The shape of the impulses produced by photocells 103 under the control of the program tape 51 is schematically indicated at 53, and it will be seen that the impulses are comparatively long, corresponding to the elongated shape of program representing tape portions a. Each impulse 53 represents a needle selecting operation required for a particular pattern to be knitted. The shape of impulses 53 is changed by devices 44 and 111, as will be explained hereinafter, and the impulses are then supplied to electromagnetic actuating means to operate selected cylinder needles. Consequently, impulses 53 are selecting impulses, and when no impulse is supplied to the actuating means 54 during passage of a needle, the respective needle will not be raised to a knitting position.

An impulse generator 59 is controlled by the axially extending projections 55 on the needle cylinder between which the cylinder needles are guided for axial movement between inoperative and knitting positions.

The needle cylinder projections 55 consist of a ferromagnetic material. Pulse generator 59 has a winding on a permanent magnet which has pole shoes forming a gap opposite the periphery of the needle cylinder. When a projection 55 passes the gap, a timing impulse is generated in. the winding of impulse generator 59 and supplied through a pulse shaper 57 and line 102 to the AND-gate 44, the pulse shaper 57 producing a rectangular pulse shape as schematically shown at 58.

FIG. 3 shows selecting impulses 53, and timing impulses 58. The selecting impulses 53 are shown to be rectangular, as if the pulses would have passed through a pulse shaper between photocell 103 and gate 44.

Since the program tape 51 may slip on transporting roller 101, exact synchronism of the movement of program representing portions a with the passage of the needles of the needle cylinder by the actuating means 54 is not assured. The timing impulses 58 are shown in FIG. 3 to be exactly spaced a time interval t while the selecting impulses 53 are not accurately centered in relation to the timing impulses 58, and are spaced distances AI +At and +At The program representing slots or transparent portions :1 of program tape 51 are selected long enough so that irrespective of a displacement of the program tape, each program impulse 53 will coincide with a short timing impulse 58. Evidently, the duration of a program representing impulse 53 should not be greater than the time interval t between timing impulses. The range of permissible deviations of the timing of the program impulses 53 is 50% of the duration of the energization of a photocell 103 by a perforation a of the program tape 51.

The AND-gate 44 produces an output signal 110 only during coincidence of a timing impulse 58 with a program representing impulse 53 so that the superimposed impulses 110 are rectangular, and are spaced from each other in accordance with the program represented by program tape 51. Selecting impulses 110 are supplied to an amplifier 111, and amplified to a great amplitude as schematically shown at 112, whereupon they are supplied to the electromagnetic actuating means 54 which, when energized by selecting impulse 112, causing raising of a cylinder needle to a knitting position, as described, for example, in the US. patent to Schmidt et al., No. 3,365,917.

For each actuator 54, a corresponding track of program representing portions a is provided on pro-gram tape 51, only one track being shown at a in FIG. 2 for the sake of simplicity. It will be understood that an actuating means 54 is provided at each knitting station of the circular knitting machine.

A photocell or photo diode 103 is associated with each track of program tape 51. However, only one series of timing impulses 58 is produced by projections 55 of needle cylinder 6 and superimposed in the AND-gates 44 on the selecting program impulses produced by photocells 103 in accordance with the tracks on the program tape. Since the AND-gate 44 produces an output impulse only if receiving simultaneously two input impulses, those timing impulses 58, for example timing impulse 58' in FIG. 3, which are not superimposed by a selecting impulse 53, are eliminated in the AND-gate 44. Consequently, the final selecting impulses 112 are arranged in a sequence and pattern determined by the program of program tape 51.

The importance of the synchronization of the final selecting impulses 112 with the movements of the knitting cylinder 56, as compared with the not yet synchronized program produced impulses 53, will be understood from the following example.

Assuming that needle cylinder 56 rotates at 18 revolutions per minute, has a diameter of 30 inches, and 1680 cylinder needles, a time period of 1.8 milliseconds is available for the selection and actuation of a cylinder needle. Considering the necessary peripheral distances between the cylinder needles due to mechanical design considerations, the impulse transmission from the program control means 51, and the actuation of the needle by the electro- 20 magnetic actuating means 54, must be carried out within a time period of less than 1 millisecond, and actually 0.5 millisecond are available for the operation of a needle. The comparatively long program depending impulses 53 cannot cause control operations of actuating means 54 at such a speed and within such a short time. Even if it were possible to produce such short impulses by program control means, any relative displacement between transporting roller 101 and needle cylinder 56, or between program tape 51 and transporting roller 101, would cause a delay or advance of the selecting impulse acting on the needle so that the next following needle or the preceding needle would be operated instead of the needle selected by the program tape.

By using only exactly spaced short portions of the program depending impulses 53, which is obtained by selecting exactly timed portions 110 of impulses 53 by means of the exactly synchronized and spaced timing impulses 58, the operation of the needles of the needle cylinder can be obtained within the extremely short necessary time period available for the selection and operation of the respective needle while passing and registering with the respective electromagnetic actuating means 54 at a knitting station.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of needle selecting arrangements for a circular knitting machine differing from the types described above.

While the invention has been illustrated and described as embodied in a needle selection synchronizing apparatus using for the actuation of needles, only portions of the program produced impulses as selecting impulses, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the followig claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. In a circular knitting machine, in combination, a needle selection synthronizing apparatus comprising a rotary needle cylinder; axially extending projections and axially extending grooves on said needle cylinder for receiving and guiding needles between inoperative and knitting positions; electromagnetic inpulse generator means located adjacent the periphery of said needle cylinder and being controlled by said projections and grooves to cyclically assume operative conditions between inoperative conditions for predetermined first time periods at exactly spaced time intervals for producing timing pulses; program control means; transmission means connecting said needle cylinder with said program control means for driving the latter in such a manner that exact synthronism cannot be maintained; switching means having operative and inoperative conditions and being controlled by said program control means in accordance with a program to assume said operative conditions for second time periods longer than said first time periods and timed so that said first time periods fall within said second time periods; and electromagnetic actuating means located adjacent the periphery of said needle cylinder for operating cylinder needles, said electromagnetic actuating means being connected into the circuit of said impulse generator means and said switching means and being energized to operate needles registering therewith only when both said impulse generator means and said switching means are in said operative conditions whereby needle operations are controlled by said electromagnetic actuat ing means in accordance with a program determined by said program control means and in exact synchronism with said needle cylinder irrespective of relative movement between said needle cylinder and said program control means.

2. An apparatus as claimed in claim 1 and including a crrcurt connecting said impulse generator means and switching means and having a source of electric energy; gate means receiving impulses from said impulse generator means, and from said switching means in said operative conditions, and being responsive to coinciding impulses to produce a selecting impulse for energizing said electromagnetic actuating means; wherein said program control means includes a transparent transporting roller means, a tape having light permeable program-representmg portions and being transported by said transporting roller means; comprising transmission means connecting said transporting roller means with said needle cylinder; wherein said switching means include a source of light for sensing said light permeable program representing portion, and photocell means receiving light passing through the same and through said transparent transporting roller means so as to produce program representing impulses supplied to said gate means; and wherein said electromagnetic impulse generator is excited by flux variation produced by said projections to create timing impulses supplied to said gate means.

3. An apparatus as claimed in claim 1 wherein said impulse generator means includes a permanent magnet having pole shoes in the proximity of said projections, and a winding on said permanent magnet so that a timing impulse is produced during passage of a projection and groove past said pole shoes of said permanent magnet.

4. An apparatus as claimed in claim 1 wherein said program control means includes a tape having program representing portions, transporting roller means for said tape, and transmission means connecting said transporting roller means with said needle cylinder.

5. An apparatus as claimed in claim 4 wherein said program representing portions of said tape are light permeable; and wherein said switching means include a source of light, and photocell means receiving light passing through said light permeable portions and producing program representing impulses.

6. An apparatus as claimed in claim 5 including an electric circuit connecting said electromagnetic impulse generator means with said switching means and having a source of electric energy; and gate means receiving timing impulses from said impulse generator means, and program representing impulses from said switching means in said operative conditions of the same, and being responsive to simultaneous impulses from both said impulse generator means and from said switching means to pr duce a selecting impulse for energizing said electromagnetic actuating means.

7. An apparatus as claimed in claim 6 wherein said electromagnetic impulse generator is located in the proximity of said projections of said needle cylinder and is excited by fiux variations produced by said projections to create timing impulses which are supplied to said gate means, said gate means including and AND-gate having an output connected with said electromagnetic actuating means.

8. An apparatus as claimed in claim 7 and including a pulse shaper connected with the output of said impulse generator for forming timing impulses of rectangular shape.

9. In a circular knitting machine, in combination, a rotary needle cylinder having a set of guiding means about the periphery thereof for guiding cylinder needles in axial direction; electromagnetic impulse generator means in the proximity of said needle cylinder controlled by said guiding means to produce timing impulses in exact synchronism with rotation of said needle cylinder; program control means driven from said needle cylinder substantially in synchronism with the rotation of the same, and producing program representing impulses; AND-gate means connected with said impulse generator and with said program control means for receiving said timing impulses and said program representing impulses, and producing a selecting impulse only during coincidence of said timing impulses with said program representing impulses; and electromagnetic actuating means receiving said selecting impulses from said AND-gate means and being energized by said selecting impulses to actuate passing cylinder needles registering therewith in accordance with the program of said program control means and at exactly timed intervals during exactly the same time periods determined by said timing impulses.

References Cited UNITED STATES PATENTS 2,944,157 7/1960 McAuslan et al. 66-154 3,263,453 8/1966 'Carrotte et al. 66-50 3,274,802 9/1966 Schmidt et al. 66-154X 3,313,128 4/1967 "Schmidt et al. 66-50 3,313,129 4/1967 Stock 66-154 3,317,735 5/1967 Elsasser 66-50 3,324,685 6/1967 Schmidt et al 66-154X 3,327,499 6/ 1967 Schmidt et al. 66-154X 2,158,536 5/1939 Fisher et al 66-50 3,262,285 7/1966 Beguin et al. 66-50 3,283,541 11/1966 De Cerjat 66-50 3,292,393 12/ 1966 Ribler 66-50 3,365,916 1/1968 Ribler et al 66-50 3,365,917 1/1968 Schmidt et al. 66-50 3,470,714 10/ 1969 Corbaz 66-50 WM. CARTER REYNOLDS, Primary Examiner 

